Eddy currents in a rectangular toroid

Eddy currents flowing in a metallic toroid of rectangular section modify the mutual resistance and mutual inductance between a pair of windings around the metal. These effects can be used to determine the metal´s conductivity. This paper presents a two-dimensional analysis of the process, using a Green´s function method to determine the magnetic field, from which the resistance and inductance are derived. The results are compared both with a one-dimensional theory and with experimental data.